What Is A Modular Synthesizer?

The modular synthesizer is a type of synthesizer consisting of separate specialized modules connected by wires (patch cords) to create a so-called patch. Every output generates a signal - an electric voltage of variable strength. Combining the signals generated by multiple modules into a common audio output allows a potentially infinite number of configurations, leading to a potentially infinite number of sounds.

There exist many different types and sub-types of modules - even modules with the same basic function will have different inputs, outputs and controls on various models. There are some standards which  manufacturers follow for their range of synthesizers; however, connecting synthesizers from different manufacturers sometimes requires converters.

Basics
Waveforms

Gates

CV

Clock